The invention relates generally to gravity dispensing systems and more particularly to proportional gravity dispensing devices for liquids.
In many applications it is desirable not to premix two or more liquids for later use but to mix the liquids only when they are ready to be used. Such is the case where the two or more liquids to be mixed will react chemically: epoxy and resin, oxidants and oxidizable materials such as bleach and detergents or bleach and color dyes. It is also desirable to mix immiscible liquids only at the time when they are to be used since a mixture of such liquids will not remain in permanent emulsion in a single mixture. Examples of such liquids are: hair dressing liqids such as an oil containing lanolin and an aqueous liquid containing alcohol; oil and vinegar used as salad dressing and mixed drinks such as fruit juice and alcoholic beverage. It is also frequently desirable for the volumes of the different liquids in the mixture to be in predetermined proportions.
In prior practice, proportional amounts of different liquids are dispensed consecutively and not simultaneously and the flow rates of the liquids are typically not controlled. In U.S. Pat. No. 2,661,870, Huenergardt discloses a container for dispensing two liquids simultaneously from two chambers of the container. Each chamber is connected by a passage to the top of the container. The ends of the passages at the top of the contaner (or outlets) have been calibrated so as to deliver predetermined portions of two liquids in the same proportion as the ration between the volumes of the two chambers. Huenergardt also discloses a container configuration wherein the two chambers are defined by two containers: an outer container containing and completely surrounding the inner container.
The dispensing container disclosed by Huenergardt, however, contains no means for venting so that when the liquids are delivered from the two chambers, apparently negative pressure may build up within the two chambers which may prevent any significant amount of liquids from being delivered. Thus, Huenergardt's container is apparently only capable of delivering small quantities of liquid and is therefore impractical for many laundry and food preparation applications. Because of the lack of venting, Huenergardt's container is not a free pouring system.
Other known types of dispensing containers include those where a predetermined volume or dosage of a liquid is dispensed. Such containers are disclosed in U.S. Pat. No. 4,226,341 (Towns et al.) and U.S. Pat. No. 4,346,823 (Eppenbach). Such containers, however, apparently do not dispense two or more different liquids simultaneously or in predetermined proportions.